My friend who works for New Line’s DVD quality control reviewed the 4-disc FOTR SE DVD and said there was no ‘isolated 5.1 sound effects mix’, nor was there an ‘isolated 5.1 music track’. He double and triple checked this when he was at work. I was so upset I bet him $100 he was incorrect.

I cannot say who he is (for fear of his job security), but he sent me things (possible audio + video things) that proved he did indeed have the disc. I even had him tell me what Elijah Wood said at around 29 minutes into the movie in the commentary. He proved he indeed had the disc.
tkathan got this bit of information for us:

I don’t know how someone can get the fact of having an isolated score and sound fx tracks wrong, but someone did.

I can’t tell you how upset people will be, and in fact I even know of people who have already sold their soundtrack CDs based on the idea that they would have the entire movie score isolated in 5.1.